fig2

Figure 2. FAK emerges as a biomarker of poor prognosis in NSCLC patients treated with EGFR-TKI. (A) Venn diagram showing genes upregulated in both the PCR array and PAMchip analyses; (B) mRNA expression of FAK was compared between H1975 and H1975OR cells using RT-qPCR. Data were analyzed by DDCt method, as described previously^[51]; (C) p-FAK levels were measured by ELISA assay in TKI-resistant vs. TKI-sensitive cells; (D) Representative IHC images illustrating p-FAK expression in NSCLC patient tissue samples: left panel showing low expression, right panel showing high expression. Scale bars: 100 µm; (E) Survival analysis of NSCLC patients treated with EGFR-TKI, comparing low vs. high p-FAK levels; (F) IHC scoring of p-FAK in 30 NSCLC tissue samples. Patients with PD or SD upon EGFR-TKI treatment were compared; (G) Expression of FAK mRNA in 14 NSCLC biopsy samples, before (pre) and after (post) treatment. Data were analyzed by a standard curve method. Statistical significance: P-values were set as follows: ^*P < 0.05, ^***P < 0.001. The graphs were created with GraphPad Prism. FAK: Focal adhesion kinase; NSCLC: non-small cell lung cancer; EGFR: epidermal growth factor receptor; TKI: tyrosine kinase inhibitor; PCR: polymerase chain reaction; mRNA: messenger RNA; H1975OR: H1975 Osimertinib resistant; RT-qPCR: reverse transcription quantitative polymerase chain reaction; DDCt: Delta Delta Ct; p-FAK: phosphorylated focal adhesion kinase; ELISA: enzyme-linked immunosorbent assay; IHC: immunohistochemistry; PD: progressive disease; SD: stable disease; MET: MET proto-oncogene, receptor tyrosine kinase.